Mesenchymal stem cells and platelet lysate in fibrin or collagen scaffold promote non‐cemented hip prosthesis integration

The objective of this study was to evaluate whether mesenchymal stem cells (MSC) and platelet lysate (PL) seeded in a fibrin or collagen scaffold could improve the new bone (NB) formation around an uncemented hip prosthesis stem in a sheep model. In vitro expanded MSC were suspended in PL and either mixed with collagen or fibrin gel as delivery vehicle. The cell–gel composites were inserted inside the femoral canal, then the prosthesis was press‐fit inserted inside the femur. Identical procedures were performed in a control group, but only the prosthesis was implanted. Histomorphometrical analysis performed 4 months after surgery indicated that the newly formed bone inside the medullary canal, between the inner cortex and the prosthetic stem, was significantly higher in the MSC–PL–collagen group (mean 18.7 ± 4.5%) and in the MSC–PL–fibrin group (mean 18.8 ± 15.2%) when compared to the control group (mean 4.6 ± 2.0%). There was a significantly higher bone–prosthesis contact in the MSC–PL–collagen group (mean 2.7 ± 2.6%) and in the MSC–PL–fibrin group (mean 2.3 ± 3.1%) compared to the control group (mean 0.2 ± 0.1%). The results indicate that MSC and PL in a fibrin or collagen scaffold can promote NB formation around an uncemented hip prosthesis stem.